With growing requirements for connectivity in a highly mobile environment, more standards and services are being rolled out (such as DVB-H, RFID, RDF, UWB, LTE etc). For this reason some believe that future mobile terminals will need to incorporate more than 20 separate antennas. It will therefore be challenging for mobile terminal designers to fit all of these antennas into the small amount of space which is available in a handset.
There are many proposals for reconfigurable antenna designs which would help to alleviate this problem. In particular, the applicants have devised a reconfigurable antenna described in WO2011/048357 which has an extremely wide tuning range. However, this antenna is only able to access two services simultaneously. For example, the antenna can only support DVB-H (470 MHz) and GSM (900 MHz) signals or DVB-H (470 MHz) and WiFi (2400 MHz) or GSM (900 MHz) and GPS (1500 MHz) but it cannot support more than two of these services simultaneously, as required by current mobile devices which can require simultaneous access to GSM, GPS and WiFi. Furthermore, this particular antenna is unlikely to be adequate for future Cognitive Radio systems which will require multi-resolution spectrum sensing.
If multi-services or multi-spectrum sensing is required in the future then one solution would be to use more reconfigurable antennas. However, as mentioned above, providing multiple antennas in a small device is impracticable and so the system designers still need to address the problem concerning the small amount of space available to provide such services.
An aim of the present invention is therefore to provide a multi-output antenna which helps to address the above-mentioned problems.